Random Quiz Questions

Question 1

The difference between sphingomylein (SM) and phosphatidylcholine (PC) is that:

Answer 1

SM backbone is derived from serine while PC backbone is glycerol

Question 2

Which of the following is a source of heterogeneity in the plasma membrane?
-Differences in the polar head groups of the lipids
-Differences in the fatty acids (nonpolar tail groups)
-Differences in the amphipathic nature of the membrane
-Two of the above
-All of the above

Answer 2

Two of the above

Question 3

Which of the following receptors involves tetramer formation during activation?

Answer 3

Receptor Tyrosine Kinases

Question 4

Activation of a receptor guanylyl cyclase can take place ____ and causes ____

Answer 4

on the cell surface or in the cytosol; an increase in the cGMP level

Question 5

Which of the following is a mechanism for activation of receptor tyrosine kinases?
-Dimerization of the receptors by a ligand dimer
-Relief of autoinhibition by ligand binding
-Change in conformation of a preformed receptor dimer induced by ligand binding
-Two of the above
-All of the above

Answer 5

All of the above

Question 6

SC binds KIT on the surface of the cell. This induces KIT dimerization and the activation of a kinase on the cytoplasmic side of the membrane. The kinase phosphorylates a number of cellular proteins that activate a pathway. In this example, KIT is a ____

Answer 6

Receptor

Question 7

In which receptor family is ceramide a product of receptor activation?

Answer 7

Sphingomyelinase-linked receptor

Question 8

Adaptation by seven-helix receptors involves which of the following?

Answer 8

Phosphorylation of the C-terminal tail

Question 9

Which kinetochore protein(s) bridge the inner and outer kinetochore group of microtubule binding proteins?

Answer 9

CENP-C

Question 10

Euchromatin is ____ densely packed than heterochromatin, is ___ accessible for transcription, and is like to be found more in the ___ of the nucleus

Answer 10

Less; more; center

Question 11

Removal of an acetyl group from ____ on histone tails causes the associated DNA to be ____ accessible for transcription

Answer 11

Lysine; less

Question 12

Ran has just entered the nucleus through a nuclear pore. Put the events below in chronological order from this event onward
1. Ran binds importin-beta
2. Ran hydrolyzes GTP
3. Ran leaves the nucleus through the nuclear pore

Answer 12

1,3,2

Question 13

What is found in the central passageway (lumen) through the nuclear pore complex?

Answer 13

The FG repeats of nucleoporins

Question 14

The GEF for Ran is located in the ___. The GAP for Ran is located in the ___

Answer 14

Nucleus; cytoplasm

Question 15

Nitric oxide (NO) is a second messenger that is synthesized when needed. Which of the following amino acids is the starting material for NO synthesis?

Answer 15

Arginine

Question 16

Which portion of the nucleus is most closely associated with the endoplasmic reticulum?

Answer 16

Outer nuclear membrane

Question 17

Which of the following is true regarding HP1?
-It binds to specific forms of modified histones
-It interacts with the lamin B receptor
-It can recruit the enzyme Suv39
-Two of the above
-All of the above

Answer 17

All of the above

Question 18

In which nuclear subdomain would you expect to find factors involved in DNA repair?

Answer 18

53BP1 nuclear bodies

Question 19

What is the role of the CaaX box found at the C-terminus of lamins?

Answer 19

It facilitates membrane anchoring of lamins

Question 20

In which phase of the ATPase cycle does myosin have a low affinity for actin filaments?

Answer 20

Myosin bound to ATP

Question 21

Disassembly of the lamin network is caused by which of the following

Answer 21

Activation of lamin depolymerase

Question 22

Which of the following is the force generating step in the myosin ATPase cycle?

Answer 22

Release of gamma phosphate

Question 23

Microtubule dynamics (polymerization and depolymerization) are highest at the plus end of the microtubule. This is the end that has __- tubulin exposed. At this end, _
-bound tubulin is more likely
to polymerize than it is to depolymerize.

Answer 23

Beta; GTP

Question 24

When AAA1 of dynein ___ the hexamer becomes more compact, causing the buttress to shift along the stalk, causing the dynein to bind ___ to the microtubule.

Answer 24

Binds ATP; weakly

Question 25

Which of the following is the force generating step in the kinesin ATPase cycle?

Answer 25

Binding of ATP